Because of its unique corrosion resistance, good processing performance and exquisite surface appearance, stainless steel has been widely used in many fields such as aerospace, energy, military, construction, petrochemical and so on. Polishing is an important part of the stainless steel plate in the decoration industry, its purpose is to get the final mirror (8K) stainless steel. 8K surface (No.8) is the mirror-polished surface, high reflectivity, clear reflection image, usually with resolution and surface defect rate to measure the quality of mirror stainless steel, general visual assessment: level 1 is the surface bright as a mirror, can clearly see the human features and eyebrows; Level 2 is the surface is bright, can see the human features and eyebrows, but the eyebrow part is not clear; Level 3 is good surface brightness, can see the person’s facial features and outline, eyebrow part blurred; Level 4 is the surface gloss, but can not see the person’s facial features; Grade 5 is gray and dull surface.
The stainless steel mirror plate is through the mirror polishing of the initial surface of the stainless steel plate BA, 2B or No.1 polishing to become similar to the mirror surface (scientific name 8K mirror or No.8). The mirror steel plate is the substrate for processing subsequent color or etched plates. mainly used in all kinds of decoration or metal optical products. The corrosion resistance of stainless steel depends on its alloy composition (chromium, nickel, titanium, silicon, manganese, etc.) and the internal structure, which plays a decisive role in the chromium element, it can form a passivation film on the surface of steel, the metal and the outside world isolation does not produce oxidation, enhance the corrosion resistance of steel plate. The number “8” in 8K refers to the proportion of the alloy content, and the letter “K” refers to the level of reflectivity achieved after polishing (K is the mirror reflection level). 8K mirror is the mirror grade of chromium-nickel alloy steel.
Common mirror stainless steel also includes 6K,10K,12K, etc., the larger the number, the finer the mirror is also higher. 6K refers to the rough grinding and polishing mirror plate, 10K refers to the fine grinding and polishing mirror panel, equivalent to the ordinary mirror; And 12K refers to the ultra-fine grinding polishing mirror panel, which can meet optical purposes. The higher the brightness, the greater the reflectivity and the less surface defects. In some non-strict singing they can be collectively referred to as 8K. The main polishing techniques used to obtain high-quality mirror stainless steel are electrolytic polishing, chemical polishing and mechanical polishing.
Electrolytic polishing is to soak in the electrolyte to obtain high-quality stainless steel on the surface of a polishing process, the stainless steel as an anode in this process, with the help of a direct current flows through the electrolyte specific solution to a metal, the anode surface to form a high resistivity of a thick mucous membrane, the thick mucous membrane in the micro concave and convex surface of stainless steel products in different thickness, Lead to the anode surface current density of the micro-distribution is not uniform, the current density in the bulge, dissolves fast, the concave current density is small, dissolve slowly, so as to reduce the surface roughness of stainless steel, improve the level and brightness, and form a passivation layer without defects. The electrolytic polishing solution must contain sufficient oxidizer and no active ions can destroy the passivation film.
The chemical polishing and electrolytic polishing principle are similar, the stainless steel is placed in a certain composition of the solution, the surface of the micro-raised part of the dissolution rate is greater than the micro-concave part of the dissolution rate, and the stainless steel surface is smooth, smooth. It can be seen that the principle of the chemical polishing method and electrolytic polishing method is basically the same, but the electrolytic polishing in the addition of voltage electrolysis under the forced action to accelerate the dissolution of the raised part, and the chemical polishing method is completely dependent on the self-corrosion ability of the solution to smooth the surface of stainless steel.
Mechanical polishing refers to the high-speed rotating polishing wheel with polishing paste to mechanically eliminate the uneven surface of stainless steel and obtain a bright surface processing. The polishing wheel is used to distinguish its granularity level according to the different kinds of cloth made by it, and the main structure forms are sutured type, folding type, and so on. Polishing paste according to polishing needs by polishing ability of chromium oxide and binder composed of green polishing paste, there are also by abrasive, organic paste, additives composed of polishing wax. Mechanical polishing is generally divided into rough polishing, fine polishing, or at the same time polishing with different polishing paste and polishing wheel, under the action of mechanical rotation, the final reflection image of clear mirror stainless steel. When the user chooses BA stainless steel for mirror polishing operation, no rough polishing process is required.